Combination knife



FIG. 1 is a top plan view of a combination knife showing my new design;

FIG. 2 is an elevation of the combination knife of FIG. 1;

FIG. 3 is an elevation of the combination knife taken from a side opposite that shown in FIG. 2;

FIG. 4 is a plan view of the combination knife taken from a side opposite that of FIG. 1;

FIG. 5 is an end view of the combination knife taken from an end opposite that of the blade; and

FIG. 6 is an end view of the combination knife taken from an end opposite that of FIG. 5. 

The ornamental design for a combination knife, as shown and described. 